The present invention relates to a novel method and device for detecting defects in the closure of vials. More specifically, the present invention discloses a novel method and device for detecting defects in the closure of encapsulated vials.
These days, especially in the pharmaceutical industry, the use of vials is widespread. The vials are generally small receptacles which can be used to contain medicines, samples, etc. in the form of liquids, powders or capsules. The vials may have different types of closure, such as encapsulated caps, screw-on caps, flip-up caps, rubber caps or similar, etc.
To prevent losses and/or contamination of the contents of the vial, it is very important to ensure the correct closure thereof. Among the defects that may occur in the closure of vials, particularly noteworthy is the lack of seal of said closure; however, this defect is not the only one, as vials having a sealed closure may have another type of defect which, over time, may ultimately compromise the integrity or seal of the closure. An example of defects of this type might be nicks in the capsule of the encapsulated vials, particularly nicks in the lower skirt of the capsule.
To prevent possible problems associated with a defective closure of the vial, quality controls of said closure must be put in place. On a small scale, manual inspection of the vials by an operator is feasible, but on a medium or large scale manual inspection is not feasible owing to obvious productivity problems. Because of this, over time various devices for automatically inspecting the closure of vials have appeared.
Patent application publication document PCT WO 02/057709 A2 discloses a method and apparatus for detecting the presence of a closure on a container and determining whether said closure is properly seated. Said apparatus includes at least two fibre optic heads positioned opposite one another on either side of a conveyor belt or other package transport mechanism. The fibre optic heads face one another across the path of travel of a package. The optical fibres of the receiving head are arranged in a rectangular shape, narrow in the horizontal direction and long in the vertical direction. The optic heads are connected to an optical sensor having an analogue output. As a package having a closure travels down the transport mechanism, the package closure interrupts portions of the light beam directed at the receiving head. The optical sensor generates an analogue trace signal as the closure moves down the conveyor. A processor samples the analogue signal and determines the presence and/or position of the closure therefrom.
Patent application publication document PCT WO 2012/061441 A1 discloses a system for inspecting the closures of packaged products employing lasers and receivers to scan multiple sides of a package, thereby measuring and determining a pass/fail status of a parameter of a package closure. In one embodiment, the system employs two lasers each emitting a beam that crosses one another, as well as product inspection path. Preferably, the parameter of a package closure which is evaluated is the separation between the lower surface of the cap and the upper surface of the neck of the vial.
The two documents mentioned above both disclose devices which inspect the closure of vials by optical means, in other words, without the need for physical contact between the inspection device and the vial, and they only evaluate the position of the cap relative to the package. Both systems are incapable of evaluating possible defects in a capsule which encloses said cap, and the use thereof is therefore not recommended for inspecting encapsulated vials.
Patent application publication document PCT WO 95/04267 A1 discloses a machine for inspecting translucent bottles or similar articles, comprising an inspection station for checking the article walls, the station being provided with an illuminating device, an imaging device and an intermediate mirror assembly which creates at least two beams, as well as a conveyor which carries the bottles in single file between the beams. In order to improve on such an inspection machine, the invention provides for a mirror assembly which creates at least three beams which illuminate the side wall of a bottle under inspection from different directions. Said device may have a first camera inspecting the side walls of the bottle and a second camera for inspecting the outline and/or height and/or colour of the bottles to be inspected.
The inspection machine disclosed by document WO 95/04267 A1 only inspects the walls of the bottles, that is, said machine does not inspect the closure thereof, and consequently is not capable of detecting defects in said closure.
Patent application publication document PCT WO 2016/202528 A1 discloses a method for inspecting containers, in particular bottles, wherein the closed containers are transported by means of a transport apparatus and closures applied to the containers are inspected with regard to tightness and/or correct seating by an inspection device. By means of an optical 3D (three-dimensional) measurement method, the inspection device at least partially senses a container together with the closure of the container and generates 3D data thereof, in particular, 3D points, 3D line elements and/or 3D surface elements. Said 3D data are processed by means of an evaluation apparatus and the tightness and/or correct seating of the closure is thereby inferred. Said 3D optical measurement method comprises 3D stereoscopic measurement by capturing images of at least a portion of the receptacle and of the closure from at least two points of view.
Document WO 2016/202528 A1 also discloses a container inspection device which comprises a transport apparatus for transporting a closed container which comprises a closure connected to said container, a 3D optical measurement device to capture a 3D image of at least a portion of the container and of the closure; and an evaluation device to process the 3D image in order to determine the tightness and correct seating of the closure in relation to the container. Said 3D optical measuring device is connected to a diffuse or structured light source and may be a camera which comprises a stereoscopic lens or two or more cameras, each comprising a lens.
Although the method and the device disclosed by document WO 2016/202528 A1 may be used for a variety of containers and closures, said document does not disclose that said method and device can be used to inspect encapsulated vials and/or encapsulated closures, and consequently neither does it disclose what parameters should be evaluated in order to be able to detect defects in the closure of encapsulated vials. In addition, said method and device have the drawback that measurement of an object in three dimensions by triangulation of points from two images requires a high computational load.